Picture of the Day

Super-slippery side up

These two steel balls sit in a pool of octane, a component of petroleum, that has been dyed yellow. Though the ball on the left has picked up streaks of the oily liquid, the ball on the right has repelled the octane thanks to a self-healing, super-slippery coating called X-SLIPS (slippery liquid-infused porous surfaces). Researchers developed this coating, which repels both water and oil, based on the slippery interiors of Nepenthes pitcher plants and the wax layer on plant leaves. To make the coating, a team of researchers from The Pennsylvania State University applied a 2.5-µm-thick layer of fluorinated silane to the sanded surface of the ball. A spritz of DuPont’s Krytox lubricant, a perfluorinated oil similar to Teflon, adheres tightly to the silane to create a surface that fends off water and oil. After damaging the coating with blasts of oxygen plasma or abusing it with 40-grit sandpaper, the researchers could restore it by simply heating it, causing the remaining silane to redistribute across the surface and re-adhere. Potential uses for the coating include use on ships or in condiment packaging.

Visit Website | Image credit: Jing Wang and Tak-Sing Wong, The Pennsylvania State University